#    Supsta
#    Copyright (c) 2014 Sebastian Dufner
#
#    This file is part of Supsta.
#
#    Supsta is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    Supsta is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <http://www.gnu.org/licenses/>.

##

module Supsta

  ##
  # Provides methods for texture stack members.

  module TextureProvider
    attr_accessor :last_compiled
    attr_reader :child
    attr_writer :mtime

    ##
    # Returns the Time of the last modification.

    def mtime
      return @mtime unless @child
      @child.mtime < @mtime ? @mtime : @child.mtime
    end

    ##
    # Returns true if the Filter was modified since the last compilation.

    def modified?
      return true unless last_compiled
      mtime > last_compiled
    end

    ##
    # Returns a Hash representing this TextureProvider.

    def to_hash
      {
        name: name,
        mtime: mtime,
        last_compiled: last_compiled,
        child: child ? child.to_hash : nil
      }
    end

  protected

    ##
    # Makes +new_child+ this TextureProvider's #child, updating #mtime in the
    # process.

    def child=(new_child)
      mtime = Time.now
      @child = new_child
    end

  end
end
